Mechanical grab



y 21, 1963 s. L. GUINOT 3,384,409

MECHANICAL GRAB Filed March 1, 1966 five/e1. 1. 60/4/07- #rraen EysUnited States Patent Office 3,384,409 Patented May 21, 1968 3,384,409MECHANICAL GRAB Gabriel L. Guinot, Le Plessis-Belleville, France,assignor to Societe Anonyme Poclain, Le Plessis-Bellevillc, France FiledMar. 1, 1966, Ser. No. 530,927 Claims priority, applicitzion France,Apr. 8, 1965,

7 Claims. (01. 294--88) ABSTRACT OF THE DISCLOSURE The invention relatesto mechanical grabs of the kind comprising a central lifting frame onwhich are articulated grab claws and rams for operating said claws.

In known grabs of this kind, the ram associated with a claw is situatedabove the claw and is connected to the upper side of the claw and to thecentral lifting frame. This means that the rams are not protected in anyway against shocks and that the overall height of the grab from the tipsof the claws to the point of articulation on the claws to the centralframe, is considerable.

The object of the present invention is to overcome these twodisadvantages thus, it aims at substantially reducing the total heightof the grab and effectively protecting the rams without creatingmaintenance difficulties.

With this object in view each claw of a grab according to the inventioncomprises a casing with an opening in its upper part, and a clawoperating ram situated.

within the said casing. One free end of the ram is connected internallyto the lower part of the claw, at a relatively short distance from thetip of said claw, and the other free end of the ram extends from theupper end of the casing, through said opening and is articulated about apivot carried by the central lifting frame of the grab.

At least a part of the wall of the casing, preferably the outer wall, isprovided with an easily removable inspection door, providing access tothe ram mounted within the casing.

A rotary coupling for pressure fluid is located between the upper partof the central frame and the hooking member of the grab assembly.

In order that the invention may be more clearly understood oneparticular embodiment thereof will now bedescribed, by way of example,with reference to the accompanying drawing which is a part elevationaland part sectional view of the grab; one half of the drawing showing aclaw of the grab in section and in its closed position while the otherhalf shows a claw of the grab in elevation and in open position.

Referring to this drawing each claw 1 or 1' comprises a hollow casing,formed by two side walls 2 integral with an inner wall 3 and an outerwall 4 and connected together by cross stays such as 5. The casingterminates at its lower end in a tip 6 formed by an expendable tooth. Atits upper end the casing is provided with an opening 7.

The claw is provided at its upper part with two perforated ears 8situated above the upper edge of the inner plate 3.

Each claw is articulated by said ears 8 to the periphery of a centralunitary frame 9 provided with regularly spaced radial connecting flanges10. Above the connecting flanges 10 the central unitary frame 9 carriesthe same number of extensions such as 11 which extend radially outwardsbeyond the connecting flanges 10.

An hydraulic ram 12 is housed within the casing of each claw. Each ofthese rams passes through the opening 7 and extends from a pivoted axis13 carried by each extension 11, to another axis 14 within the casing ata relatively short distance from the tip 6. Preferably, the free end ofthe cylinder of the ram 12 is connected to the axis 14 while the freeend of its piston rod is articulated about the axis 13.

The central unitary frame 9 to which the connecting flanges 10 and theextensions 11 are fixed, is surmounted by a pivot constituting a rotarycoupling, designated generally by the reference 15, comprisingessentially a sleeve 9a connected with the frame 9 and on the inside ofwhich pivots a swivel pin 9b fixed to the supporting hook member 16 ofthe grab.

Fluid for operating the rams is supplied to the rotary coupling 15through a flexible pipe 17 and is discharged by a set of other flexiblepipes 18 each feeding a cylinder of each ram. One set of fluid lines 17and 18 intercommunicate through a fluid passageway 19 in the rotarycoupling 15 and the second set of fluid lines 17 and 18intercomrnunicate through a second fluid passageway 19a in the rotarycoupling.

The operation is as follows: first, due to the rotary coupling 15, thegrab can execute a complete rotation about its axis of symmetry. Whenthe rams are in the extended position, the claws are in the closedposition as shown by the reference 1.

When the rams are in the retracted position, each claw is pulled upwardsby a force exerted in the direction from the axis 14 to the axis 13which forces it to pivot about its own axis of articulation. The ramalso pivots about its axis 13 and the claw-ram assembly finally attainsthe open position shown by the reference 1'.

The outer wall -4 is formed as an easily removable inspection doorproviding access to the interior of the claw for inspection andmaintenance of the rams which in service are protected against shocks.

It will be understood that this arrangement in accordance with theinvention provides a grab of reduced overall height in comparison tothat of known grabs. In effect, the axis of articulation 13 is removedvertically very little from the axis of articulation of the claws. Inthis respect it will be noted that the relative disposition of said twoaxes does not in any way have to be as shown in the figure. These axesmay, for example, be positioned in the same horizontal plane or the axisof articulation of the rams may even be positioned below the axis ofarticulation of the claws. The latter arrangement is particularlysuitable if it is desired to reverse the mode of action of the rams byinterchanging the articulation axes in question. The extension of therams will correspond to the opening of the claws and their retraction tothe closing thereof.

It will thus be understood, the invention is capable of numerouspractical variations and modifications, without departing from the scopeof the invention as defined in the appended claims.

I claim:

1. A mechanical grab comprising a central unitary lifting frame, grabclaws articulated to said frame, rams for operating said claws, meansfor supplying operating fluid to said rams, each claw comprising ahollow casing having closed sides almost totally shielding an operatingram and an opening in the upper end thereof, each claw operating rambeing housed within one of said casings having one end of said ramconnected to the lower part of the claw and the other end of said ramextending through said opening in said casing and being articulatedabout a pivot carried by said central lifting frame.

2. A mechanical grab according to claim 1, wherein means for supplyingfluid under pressure to the operating rams comprises a rotary couplingdisposed between said central frame and a supporting hook member for thegrab.

3. A mechanical grab comprising a central unitary lifting frame, grabclaws articulated to said frame, rams for operating said claws, meansfor supplying operating fluid to said rams, each claw comprising ahollow casing having closed sides almost totally shielding an operatingram and an opening in the upper end thereof, each claw operating rambeing housed within one of said casings having one end of said ramconnected to the lower part of the claw and the other end of said ramextending through said opening in said casing and being articulatedabout a pivot carried by a radial extension of said central liftingframe and located above and at a greater radial distance from the axisof said central frame than the axis about which the claw is articulatedto said frame.

4. A mechanical grab according to claim 3, wherein means for supplyingfluid under pressure to the operating rams comprises a rotary couplingdisposed between said central frame and a supporting hook member for thegrab.

5. A mechanical grab according to claim 3, wherein said casing isprovided with a removable door providing access to the ram within saidcasing.

6. A mechanical grab according to claim 4, wherein said casing isprovided with a door providing access to the interior of said casing.

7. A mechanical grab comprising a central unitary lifting frame, grabclaws articulated to said frame, rams for operating said claws means forsupplying operating fluid to said rams, each claw comprising a hollowcasing having closed sides almost totally shielding an operating ram andan opening in the upper end thereof, each claw operating ram beinghoused within said casing with one end of said ram connected to thelower part of one of said claws and the other end of said ram extendingthrough said opening in said casing and being articulated about a pivotcarried by said central lifting frame, said casing having an easilyremovable door providing access to the interior of said casing.

References Cited UNITED STATES PATENTS 2,725,996 12/1955 Britton 2l4l472,911,251 11/1959 Osborn 294106 X 2,959,444 11/1960 Callender 294-88 XFOREIGN PATENTS 1,202,736 7/1959 France.

ROBERT G. SHERIDAN, Primary Examiner.

GERALD M. FORLENZA, Examiner.

F. E. WERNER, Assistant Examiner.

